#!/usr/bin/python
# -*- coding: utf-8 -*-

# (c) 2012, Michael DeHaan <michael.dehaan@gmail.com>
#
# This file is part of Ansible
#
# Ansible is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Ansible is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Ansible.  If not, see <http://www.gnu.org/licenses/>.

import os
import tempfile

DOCUMENTATION = '''
---
module: copy
version_added: "historical"
short_description: Copies files to remote locations.
description:
     - The M(copy) module copies a file on the local box to remote locations. Use the M(fetch) module to copy files from remote locations to the local box. If you need variable interpolation in copied files, use the M(template) module.
options:
  src:
    description:
      - Local path to a file to copy to the remote server; can be absolute or relative.
        If path is a directory, it is copied recursively. In this case, if path ends
        with "/", only inside contents of that directory are copied to destination.
        Otherwise, if it does not end with "/", the directory itself with all contents
        is copied. This behavior is similar to Rsync.
    required: false
    default: null
    aliases: []
  content:
    version_added: "1.1"
    description:
      - When used instead of 'src', sets the contents of a file directly to the specified value.
        This is for simple values, for anything complex or with formatting please switch to the template module.
    required: false
    default: null
  dest:
    description:
      - Remote absolute path where the file should be copied to. If src is a directory,
        this must be a directory too.
    required: true
    default: null
  backup:
    description:
      - Create a backup file including the timestamp information so you can get
        the original file back if you somehow clobbered it incorrectly.
    version_added: "0.7"
    required: false
    choices: [ "yes", "no" ]
    default: "no"
  force:
    description:
      - the default is C(yes), which will replace the remote file when contents
        are different than the source. If C(no), the file will only be transferred
        if the destination does not exist.
    version_added: "1.1"
    required: false
    choices: [ "yes", "no" ]
    default: "yes"
    aliases: [ "thirsty" ]
  directory_mode:
    description:
      - When doing a recursive copy set the mode for the directories. If this is not set we will use the system
        defaults. The mode is only set on directories which are newly created, and will not affect those that
        already existed.
    required: false
    version_added: "1.5"
  remote_src:
    description:
      - If False, it will search for src at originating/master machine, if True it will go to the remote/target machine for the src. Default is False.
      - Currently remote_src does not support recursive copying.
    choices: [ "True", "False" ]
    required: false
    default: "no"
    version_added: "2.0"
  follow:
    required: false
    default: "no"
    choices: [ "yes", "no" ]
    version_added: "1.8"
    description:
      - 'This flag indicates that filesystem links, if they exist, should be followed.'
extends_documentation_fragment:
    - files
    - validate
author:
    - "Ansible Core Team"
    - "Michael DeHaan"
notes:
   - The "copy" module recursively copy facility does not scale to lots (>hundreds) of files.
     For alternative, see synchronize module, which is a wrapper around rsync.
'''

EXAMPLES = '''
# Example from Ansible Playbooks
- copy: src=/srv/myfiles/foo.conf dest=/etc/foo.conf owner=foo group=foo mode=0644

# The same example as above, but using a symbolic mode equivalent to 0644
- copy: src=/srv/myfiles/foo.conf dest=/etc/foo.conf owner=foo group=foo mode="u=rw,g=r,o=r"

# Another symbolic mode example, adding some permissions and removing others
- copy: src=/srv/myfiles/foo.conf dest=/etc/foo.conf owner=foo group=foo mode="u+rw,g-wx,o-rwx"

# Copy a new "ntp.conf file into place, backing up the original if it differs from the copied version
- copy: src=/mine/ntp.conf dest=/etc/ntp.conf owner=root group=root mode=644 backup=yes

# Copy a new "sudoers" file into place, after passing validation with visudo
- copy: src=/mine/sudoers dest=/etc/sudoers validate='visudo -cf %s'
'''

RETURN = '''
dest:
    description: destination file/path
    returned: success
    type: string
    sample: "/path/to/file.txt"
src:
    description: source file used for the copy on the target machine
    returned: changed
    type: string
    sample: "/home/httpd/.ansible/tmp/ansible-tmp-1423796390.97-147729857856000/source"
md5sum:
    description: md5 checksum of the file after running copy
    returned: when supported
    type: string
    sample: "2a5aeecc61dc98c4d780b14b330e3282"
checksum:
    description: checksum of the file after running copy
    returned: success
    type: string
    sample: "6e642bb8dd5c2e027bf21dd923337cbb4214f827"
backup_file:
    description: name of backup file created
    returned: changed and if backup=yes
    type: string
    sample: "/path/to/file.txt.2015-02-12@22:09~"
gid:
    description: group id of the file, after execution
    returned: success
    type: int
    sample: 100
group:
    description: group of the file, after execution
    returned: success
    type: string
    sample: "httpd"
owner:
    description: owner of the file, after execution
    returned: success
    type: string
    sample: "httpd"
uid:
    description: owner id of the file, after execution
    returned: success
    type: int
    sample: 100
mode:
    description: permissions of the target, after execution
    returned: success
    type: string
    sample: "0644"
size:
    description: size of the target, after execution
    returned: success
    type: int
    sample: 1220
state:
    description: state of the target, after execution
    returned: success
    type: string
    sample: "file"
'''

def split_pre_existing_dir(dirname):
    '''
    Return the first pre-existing directory and a list of the new directories that will be created.
    返回真实存在的目录和不存在[将要创建的]目录列表
    '''

    head, tail = os.path.split(dirname)
    if not os.path.exists(head):
        (pre_existing_dir, new_directory_list) = split_pre_existing_dir(head)
    else:
        return (head, [ tail ])
    new_directory_list.append(tail)
    return (pre_existing_dir, new_directory_list)


def adjust_recursive_directory_permissions(pre_existing_dir, new_directory_list, module, directory_args, changed):
    '''
    Walk the new directories list and make sure that permissions are as we would expect
    递归设置目录权限
    '''

    if len(new_directory_list) > 0:
        working_dir = os.path.join(pre_existing_dir, new_directory_list.pop(0))
        directory_args['path'] = working_dir
        changed = module.set_fs_attributes_if_different(directory_args, changed)
        changed = adjust_recursive_directory_permissions(working_dir, new_directory_list, module, directory_args, changed)
    return changed


def main():
    """
    代码流程：
    1. 使用内置的模块类定义模块
       根据定义从实际环境中获取参数

    2. 参数1 源可用性测试
       参数2 确定复制目标

    3. 处理其他可选参数

    4.  执行复制操作
        复制完成后设置文件属性

    5.  获取指定参数状态，输出执行结果
    """
    # 使用内置的模块类定义模块
    module = AnsibleModule(
        # not checking because of daisy chain to file module
        argument_spec = dict(
            src               = dict(required=False),
            original_basename = dict(required=False), # used to handle 'dest is a directory' via template, a slight hack
            content           = dict(required=False, no_log=True),
            dest              = dict(required=True),
            backup            = dict(default=False, type='bool'),
            force             = dict(default=True, aliases=['thirsty'], type='bool'),
            validate          = dict(required=False, type='str'),
            directory_mode    = dict(required=False),
            remote_src        = dict(required=False, type='bool'),
        ),
        add_file_common_args=True,
        supports_check_mode=True, #支持测试模式【ansible -C】
    )
    # 从模块中对变量取值
    src    = os.path.expanduser(module.params['src'])
    dest   = os.path.expanduser(module.params['dest'])
    backup = module.params['backup']
    force  = module.params['force']
    original_basename = module.params.get('original_basename',None)
    validate = module.params.get('validate',None)
    follow = module.params['follow']
    mode   = module.params['mode']
    remote_src = module.params['remote_src']
    # 原路径可用性测试
    if not os.path.exists(src):
        module.fail_json(msg="Source %s not found" % (src))
    if not os.access(src, os.R_OK):
        module.fail_json(msg="Source %s not readable" % (src))
    if os.path.isdir(src):
        module.fail_json(msg="Remote copy does not support recursive copy of directory: %s" % (src))
    # 原路径校验和
    checksum_src = module.sha1(src)
    checksum_dest = None
    # Backwards compat only.  This will be None in FIPS mode
    try:
        md5sum_src = module.md5(src)
    except ValueError:
        md5sum_src = None

    changed = False

    # Special handling for recursive copy - create intermediate dirs
    # 如果目标目录【以路径符结束】不存在则创建并赋予相应权限
    if original_basename and dest.endswith(os.sep):
        dest = os.path.join(dest, original_basename)
        dirname = os.path.dirname(dest) #获取目标目录
        if not os.path.exists(dirname) and os.path.isabs(dirname):
            (pre_existing_dir, new_directory_list) = split_pre_existing_dir(dirname)
            os.makedirs(dirname)
            directory_args = module.load_file_common_arguments(module.params)
            directory_mode = module.params["directory_mode"]
            if directory_mode is not None:
                directory_args['mode'] = directory_mode
            else:
                directory_args['mode'] = None
            adjust_recursive_directory_permissions(pre_existing_dir, new_directory_list, module, directory_args, changed)
    # 目标存在的情况，目标最终拼接为文件
    if os.path.exists(dest):
        if os.path.islink(dest) and follow: #目标为软连接时获取真实目录或文件位置
            dest = os.path.realpath(dest)
        if not force:
            module.exit_json(msg="file already exists", src=src, dest=dest, changed=False)
        if (os.path.isdir(dest)): #目标拼接【最终为文件形式】
            basename = os.path.basename(src)
            if original_basename:
                basename = original_basename
            dest = os.path.join(dest, basename)
        if os.access(dest, os.R_OK): #测试目标是否可读
            checksum_dest = module.sha1(dest)
    else: #目标目录是否不可访问
        if not os.path.exists(os.path.dirname(dest)):
            try:
                # os.path.exists() can return false in some
                # circumstances where the directory does not have
                # the execute bit for the current user set, in
                # which case the stat() call will raise an OSError
                os.stat(os.path.dirname(dest))
            except OSError, e:
                if "permission denied" in str(e).lower():
                    module.fail_json(msg="Destination directory %s is not accessible" % (os.path.dirname(dest)))
            module.fail_json(msg="Destination directory %s does not exist" % (os.path.dirname(dest)))
    # 目标是否不可写
    if not os.access(os.path.dirname(dest), os.W_OK): 
        module.fail_json(msg="Destination %s not writable" % (os.path.dirname(dest)))

    backup_file = None
    # 源和目标不一致或目标是一个链接则执行复制操作，否则直接返回结果
    if checksum_src != checksum_dest or os.path.islink(dest): 
        if not module.check_mode: #不支持测试
            try:
                if backup: #备份目标文件
                    if os.path.exists(dest):
                        backup_file = module.backup_local(dest)
                # allow for conversion from symlink.
                if os.path.islink(dest): #删除链接，建立文件
                    os.unlink(dest)
                    open(dest, 'w').close()
                if validate: #测试辅助结果有效性
                    # if we have a mode, make sure we set it on the temporary
                    # file source as some validations may require it
                    # FIXME: should we do the same for owner/group here too?
                    if mode is not None:
                        module.set_mode_if_different(src, mode, False)
                    if "%s" not in validate:
                        module.fail_json(msg="validate must contain %%s: %s" % (validate))
                    (rc,out,err) = module.run_command(validate % src)
                    if rc != 0:
                        module.fail_json(msg="failed to validate", exit_status=rc, stdout=out, stderr=err)
                if remote_src: #是跨主机复制还是远端的本地复制
                    _, tmpdest = tempfile.mkstemp(dir=os.path.dirname(dest))
                    shutil.copy2(src, tmpdest)
                    module.atomic_move(tmpdest, dest)
                else:
                    module.atomic_move(src, dest)
            except IOError: #文件系统错误，复制失败
                module.fail_json(msg="failed to copy: %s to %s" % (src, dest), traceback=traceback.format_exc())
        changed = True
    else:
        changed = False
    # 定义结果输出参数
    res_args = dict(
        dest = dest, src = src, md5sum = md5sum_src, checksum = checksum_src, changed = changed
    )
    if backup_file:
        res_args['backup_file'] = backup_file

    module.params['dest'] = dest
    # 设置目标文件属性【不支持测试模式】
    if not module.check_mode:
        file_args = module.load_file_common_arguments(module.params)
        res_args['changed'] = module.set_fs_attributes_if_different(file_args, res_args['changed'])

    module.exit_json(**res_args)

# import module snippets
from ansible.module_utils.basic import *
main()
